Widows whose husbands died after receiving contaminated NHS blood are urging the government to close a loophole which denies them access to financial assistance. Around 200 women in the UK, many of whom are pensioners and living in severe hardship, are excluded from the fund because their partners, who all suffered from haemophilia, died from hepatitis C complications before an official cut-off date to be considered for compensation. Had they died later or from an HIV-related illness, they would have been entitled to support.

The women are stepping up their campaign after the announcement on Monday that there is to be an independent public inquiry into the supply of tainted blood products to haemophiliacs in the UK.

For the past 15 years, The Observer has supported calls for an inquiry and adequate compensation for those affected in what the Labour peer Lord Robert Winston has described as the worst treatment disaster in the history of the NHS.

More than 4,800 haemophiliacs in Britain were infected with hepatitis C, and 1,200 of those also contracted HIV after being given contaminated blood products during the Eighties and early Nineties. More than 1,700 have since died, and many more are terminally ill. Campaigners say they have suffered extreme financial hardship because most of them are uninsurable, unemployable and unable to make adequate provision for their dependants.

Successive governments have ruled out inquiries but they have established two funds to help those affected - the Skipton Fund for those infected with hepatitis and the MacFarlane Trust for those who contracted HIV. All but the group of women known as 'hep C widows' have received or are entitled to some form of financial assistance from one of the funds.

The anomaly in the scheme is highlighted by the case of Maureen Murphy, a 69-year-old widow from Liverpool. Her husband, William, was one of three brothers with haemophilia who died after receiving contaminated blood. The widows and dependants of his two brothers, who contracted HIV, have received support.

However, because her husband contracted hepatitis C, which is now regarded as a more deadly disease in the western world than HIV, from the tainted blood and died before August 2003, Mrs Murphy is not entitled to any form of financial help. 'This is such an unjust and indefensible situation,' Mrs Murphy said. 'This is a dreadful thing to say but in the lottery of NHS blood infection, it would have been easier if my husband had got HIV rather than hepatitis C.'

Mrs Murphy gave up her work to become a full-time carer for her husband. Because of the problems surrounding haemophilia, they were unable to take out insurance policies or mortgage protection. Greg Murphy, her son, said the government had created a 'deplorable caveat'. 'Unlike widows of HIV victims, who were rightly compensated my mum has never received a penny. She has suffered the same pain at the loss of her husband. How can the government possibly decide that her suffering is less because he died from hepatitis rather than HIV?'

Harriet Bullock, who is in her seventies and who lost her husband, Ken, eight years ago, said the situation had devastated her family's life .'I feel so angry that there is a small group of us who are excluded simply because our husbands died before the government decided to create the fund. No one has ever said sorry. I can't yet begin to mourn Ken.'

Lord Morris of Manchester, president of the Haemophilia Society, who initiated the public inquiry after years of campaigning, said: 'It is a gross anomaly that widows of those infected with hepatitis C are excluded. It illustrates the piecemeal way this tragedy has been dealt with.'

A spokesman for the Department of Health said there were no plans to offer financial support to the widows, and stressed that the scheme was designed to make lump sum payments to those living with hepatitis C and not to compensate for bereavement.